Mahshid Alsadat Mousavian; Mohammad Mehdi Riyahi; Ali Haghighi
Abstract
To analyze transient flows, continuity and momentum equations must be solved. Due to the non-linear friction term in the momentum equation, numerical methods such as method of characteristics (MOC) are used to analyze the problem in thetime domain. Although numerical methods are easy to use, but they ...
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To analyze transient flows, continuity and momentum equations must be solved. Due to the non-linear friction term in the momentum equation, numerical methods such as method of characteristics (MOC) are used to analyze the problem in thetime domain. Although numerical methods are easy to use, but they are numerically expensive and time-consuming, especially for advanced applications of transient analysis, e.g., real-time evaluations and fault detection algorithms, including inverse problem solutions. To cope with mentioned problems, an approximate analytical solution should be investigated, which is not required high computational time. To this end, the nonlinear equations should be linearized. Thus, the focus of this paper is to investigate the linearization methods. Therefore, four different linearization methods are applied and the resultingequations of each method in different RPV systems are solved. The efficiency of each method is compared with the results obtained from the numerical analysis of nonlinear governing equations. The results show that linearized water hammerequations provide reasonable results in early pressure wave cycles. The obtained results show that the coefficient of determination (R2) of the linearized models changes from 0.92 to 0.99. Also, by comparing the results of linearization modelswith each other, the linearized momentum equation in the time domain by replacing the mean velocity instead of the instantaneous velocity is the most accurate model which R2 is 0.999452.
Mobin Eftekhari; Mohammad Akbari
Abstract
Detection of aquifer vulnerable areas can highlight preventive actions for groundwater contamination. Different models have been presented for the evaluation of vulnerability that one of the most regular and well-known models of the overlapping index as the SINTACS-LU (Soggiacence, actual infiltration, ...
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Detection of aquifer vulnerable areas can highlight preventive actions for groundwater contamination. Different models have been presented for the evaluation of vulnerability that one of the most regular and well-known models of the overlapping index as the SINTACS-LU (Soggiacence, actual infiltration, non saturated zone, typology of overburden, hydrogeological characteristics of the aquifer, hydraulic conductivity, topographic Slope) model was considered in this research. In fact, this model has been extended based on the impact of land use parameters in the vulnerability evaluation. Purpose of this study is the qualitative evaluation of Birjand plain aquifer vulnerability using the SINTACS-LU model. For this, the Birjand plain aquifer in the statistical periods of 2013-2018 has been evaluated. According to the results of this assessment, the SINTACS-LU vulnerability zoning map reveals that 15 percent of the studied region has the vulnerability of medium to high, 75 percent of the area has a high vulnerability, and 10 percent has the too high vulnerability. In order to the verification of the SINTACS-LU model, the relationship between the vulnerability index and the obtained nitrate concentration values from 21 groundwater samples were assessed. The correlation coefficient between the SINTACS-LU vulnerability index and the nitrate concentration was 75 percent, which indicates the appropriate correlation of this model with the nitrate concentration as the indicator of the groundwater contamination.
Adeleh Afroozan; Ali Mohammad-khah; Farhad Shirini
Volume 2, Issue 2 , December 2015, , Pages 150-155
Abstract
In current study, sulfonic acid-functionalized ordered nanoporous Na+-Montmorillonite (SANM) has been utilized as the adsorbent for the removal of a cationic dye, methylene blue (MB), from aqueous solution using the batch adsorption technique under different conditions such as temperature, adsorbent ...
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In current study, sulfonic acid-functionalized ordered nanoporous Na+-Montmorillonite (SANM) has been utilized as the adsorbent for the removal of a cationic dye, methylene blue (MB), from aqueous solution using the batch adsorption technique under different conditions such as temperature, adsorbent dosage, initial dye concentration, contact time, and pH solution. The optimum sorption conditions were found as following: contact time 10 min, initial dye concentration 800 mg/L, adsorbent dose 0.3 g and temperature 25 °C. The results indicate that the process is pH independent. The sorption capacity was 500 mg/g for this dye. Different thermodynamic parameters i.e., changes in standard free energy, enthalpy, and entropy have also been evaluated. The ΔHads and ΔSads values are thus found to be +38240 (J/mol) and ΔSads138.43 J/K, respectively, while the ΔGads values is -3012.14 J in 298 K and it has been found that the reaction was spontaneous and endothermic in nature. On the other hand, Kinetic parameters have been investigated with pseudo first and second order. The result of experimental data indicates that pseudo second order equation fit better than the other.
Azadeh Gholami; Hossein Bonakdari; Ali Akbar Akhtari
Volume 3, Issue 1 , June 2016, , Pages 193-200
Ali Mahdavi
Volume 3, Issue 2 , December 2016, , Pages 241-246
Sultan Noman Qasem; Isa Ebtehaj; Hossien Riahi Madavar
Abstract
Flow through open channels can contain solids. The deposition of solids occasionally occurs due to insufficient flow velocity to transfer the solid particles, causing many problems with transfer systems. Therefore, a method to determine the limiting velocity (i.e. Fr) is required. In this paper, three ...
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Flow through open channels can contain solids. The deposition of solids occasionally occurs due to insufficient flow velocity to transfer the solid particles, causing many problems with transfer systems. Therefore, a method to determine the limiting velocity (i.e. Fr) is required. In this paper, three alternative, hybrid evolutionary algorithm methods, including differential evolution (DE), genetic algorithm (GA) and particle swarm optimization (PSO) based on the adaptive network-based fuzzy inference system are presented: ANFIS-GA, ANFIS-DE and ANFIS-PSO. In these methods, evolutionary algorithms optimize the membership functions, and ANFIS adjusts the premises and consequent parameters to optimize prediction performance. The performance of the proposed methods is compared with that of the general ANFIS using three different datasets comprising a wide range of data. The results show that the hybrid models (ANFIS-GA, ANFIS-DE and ANFIS-PSO) are more accurate than general ANFIS in training with a hybrid algorithm (hybrid of back propagation and least squares). Among the evolutionary algorithms, ANFIS-PSO performed the best (R2=0.976, RMSE=0.26, MARE=0.057, BIAS=-0.004 and SI=0.059).
Ali Beryani; Alireza Pardakhti; Mojtaba Ardestani; Mohammad Ali Zahed
Abstract
A bench-scale study was designed for removal of Methyl Tertio Butyl Ether (MTBE) and benzene from south of Tehran groundwater. The experiments were implemented on a one-dimensional soil column with similar chemical and physical conditions of the region. Fenton’s chemical oxidation with stabilized ...
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A bench-scale study was designed for removal of Methyl Tertio Butyl Ether (MTBE) and benzene from south of Tehran groundwater. The experiments were implemented on a one-dimensional soil column with similar chemical and physical conditions of the region. Fenton’s chemical oxidation with stabilized nano zero-valent iron particles (S-NZVI) as catalyst was used. For treatment of groundwater polluted with 2 mg L-1 MTBE and 1 mg L-1 benzene, optimum concentrations of H2O2 and S-NZVI were 1500 and 300 mg L-1, respectively. The optimum concentrations led to 78 % elimination of MTBE and 87 % of benzene. Hazardous by-products (acetone and tertio-butyl alcohol) concentrations were less than 0.1 mg L-1, which were considered to be negligible. The soil permeability was reduced to 30 % after removal process. To increase the system efficiency and reduce the consumption of iron, the reaction environment was acidified down to pH = 3.2 led to removal efficiency of 90 % and 96 % for MTBE and benzene, respectively. The scavengers (ions) reduced the system efficiency up to 15 %. This study indicates that theoretically the MTBE and benzene could be removed from groundwater using Fenton’s chemical oxidation with S-NZVI.
Majid Heydari; Jalal Sadeghian; Saeid Shabanlou
Abstract
Manning roughness coefficient is one of the most important parameters in designing water conveyance structures. Unsuitable selection of this coefficient brings up some mistakes. This research aims to present a method to determine the Manning roughness coefficient based on a combination of optimization ...
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Manning roughness coefficient is one of the most important parameters in designing water conveyance structures. Unsuitable selection of this coefficient brings up some mistakes. This research aims to present a method to determine the Manning roughness coefficient based on a combination of optimization algorithm of simulated annealing (SA) with gradually varied flow equations. Therefore, in a lab rectangular flume of 12 m, 60 cm and 65 cm in length, width and height with fixed channel bed slope of 0.0002, nine series of water level profiles were carried out. Then, an objective function based on observed and calculated water level gradient was defined to decide on manning roughness coefficient while it was minimized with simulated annealing optimization method. The values of objective function parameters were discussed by sensitivity analysis and the most optimal objective function was obtained. To measure the accuracy of coefficient obtained, Statistics indices of R2, Root mean square error (RMSE), Mean bias error (MBE), d were used. The results showed that manning roughness coefficient has a great accuracy.
Behnaz Jalili; Seyed Mehdi Borghei; Vahid Vatanpour; Christopher Sarkizi
Abstract
Wastewater reuse has been attracted a lot of attention in recent years especially in places with low water availability. The effluents that were considered to be discharged are now could be used as potential sources of reusable water. In this study, variables affecting the removal of ethylene glycol ...
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Wastewater reuse has been attracted a lot of attention in recent years especially in places with low water availability. The effluents that were considered to be discharged are now could be used as potential sources of reusable water. In this study, variables affecting the removal of ethylene glycol (EG) by adsorption on granular activated carbon (GAC) from the synthetic wastewater solutions were optimized by response surface methodology (RSM) using a central composite design. The investigated factors were temperature, EG concentration, contact time, activated carbon amount and granular size. Adsorption kinetic was also studied and an acceptable correlation between Langmuir model and experimental data was observed. As a result, a modified third degree equation was proposed and used to find the optimized condition. The maximum adsorption was achieved at 27.7 ºC with 0.8 g of 20-30 mesh activated carbons for an EG feed concentration of 135 mg/L at 210 minutes.
Masoud Shariati-Rad; Mohsen Irandoust; Somayyeh Amri; Mostafa Feyzi; Fattaneh Ja’fari
Volume 1, Issue 1 , March 2014, , Pages 6-12
Abstract
A method was developed for removal, preconcentration and spectrophotometric determination of trace amounts of methyl red based on SiO2-coated Fe3O4magnetic nanoparticles. The influence of pH, dosage of adsorbent and contact time on the adsorption of dye was explored by central composite design. The kinetic ...
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A method was developed for removal, preconcentration and spectrophotometric determination of trace amounts of methyl red based on SiO2-coated Fe3O4magnetic nanoparticles. The influence of pH, dosage of adsorbent and contact time on the adsorption of dye was explored by central composite design. The kinetic data were analyzed based on the Langmuir and Freundlich adsorption isotherms. The Langmuir model was fitted well to data and the maximum monolayer capacity q max of 49.50 mg g−1 was calculated. The results showed that desorption efficiencies of higher than 99% can be achieved in a short contact time of 3 min and in one step elution using 2.0 mL of 0.1 mol L−1 NaOH. The magnetic nanoparticles were washed with deionized water and reused for two successive removal processes with removal efficiencies more than 90%. Then desorbed dye was determined spectrophotometrically. The calibration curve was linear in the range of 0.025–0.250 mg L−1 of dye with a correlation coefficient of 0.9922. The relative standard deviations obtained upon application of the method to the real samples were lower than 0.7%. A preconcentration factor of the method was 50.
Seyed Mohammad Ashrafi; Maral Mahmoudi
Abstract
In this study, water resources system of Great Karun watershed is modelled as a semi-distributed system considering the diversity of demand sites downstream of Olya Gotvand and Dez reservoirs in southwest of Iran. The main aim of the present study is to develop a basin's decision-support system to assist ...
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In this study, water resources system of Great Karun watershed is modelled as a semi-distributed system considering the diversity of demand sites downstream of Olya Gotvand and Dez reservoirs in southwest of Iran. The main aim of the present study is to develop a basin's decision-support system to assist decision-makers in examining the impacts of different operating policies prior to their implementation. According to the basic characteristics of the system, a decision-support system is developed applying water evaluation and planning system (WEAP) model. Calibration of the developed model is important based on the Demand sites diversity and the spatial scale of the modelled basin. To calibrate the simulation model, a Harmony Search (HS) Optimization Algorithm is applied in an innovative framework. The comparison of the achieved results with the observed data indicates the accuracy of the calibrated model. It is also clear that, regardless of the quality parameters of the flow, all urban, industrial, agricultural and aquaculture demands at the basin level have been satisfactorily fulfilled in the study period. Of course, it should be noted that by taking into account the qualitative criteria, the obtained results will obviously change.
Babak Sanahmadi; Majeid Heydari; Saeed Gohari; Saeid Shabanlou
Abstract
In this paper, the flow in the vicinity of rectangular side orifices placed in main channels is estimated by means of the FLOW-3D model. To reconstruct the flow free surface, the volume of fluid (VOF) approach is utilized. In addition, the standard k-ε and RNG k-ε turbulence models are ...
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In this paper, the flow in the vicinity of rectangular side orifices placed in main channels is estimated by means of the FLOW-3D model. To reconstruct the flow free surface, the volume of fluid (VOF) approach is utilized. In addition, the standard k-ε and RNG k-ε turbulence models are employed to predict turbulence flow. According to the results obtained from the numerical modeling, the RNG k-ε turbulence model has higher accuracy than the standard k-ε. The analysis of the numerical modeling results proved that this model forecasts the discharge coefficient of side weirs with suitable accuracy. On the other hand, the mean absolute percent error (MAPE) is calculated equal to 12.204%. Also, the maximum pressure is simulated near the main channel bed. Moreover, the minimum pressure is estimated near the flow free surface. Regarding the numerical simulations, the maximum turbulence energy state occurs near the inlet of the side orifice and by increasing the side orifice dimensions the flow field turbulence energy value increases.
Fariborz Yosefvand; Saeid Shabanlou
Abstract
In this study, for the first time, groundwater level (GWL) variations of the Sarab-e Qanbar well located in the city of Kermanshah, are simulated over a 13-year period by a hybrid model named WANFIS (wavelet-adaptive neuro fuzzy inference system). In order to develop the hybrid model, the wavelet transform ...
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In this study, for the first time, groundwater level (GWL) variations of the Sarab-e Qanbar well located in the city of Kermanshah, are simulated over a 13-year period by a hybrid model named WANFIS (wavelet-adaptive neuro fuzzy inference system). In order to develop the hybrid model, the wavelet transform and the adaptive neuro fuzzy inference system (ANFIS) model are utilized. Furthermore, the 9 and 4 year data are used for training and testing the artificial intelligence models, respectively. Moreover, the effective lags are detected by the autocorrelation function (ACF) and then eight different models are developed for each of the ANFIS and WANFIS models using them. After that, all mother wavelets are evaluated and Dmey mother wavelet is chosen as the most optimal. For this mother wavelet, the values of scatter index (SI), variance account for (VAF) and Root mean square error (RMSE) are obtained 0.192, 94.951 and 3.117, respectively. Next, the superior model is detected through the analysis of the results obtained by all ANFIS and WANFIS models. The superior model estimates the objective function values with reasonable accuracy. For example, the correlation coefficient (R), Scatter Index (SI) and variance account for (VAF) for this model are obtained 0.974, 0.192 and 94.951, respectively. The modeling results indicate that the wavelet transform noticeably enhances the ANFIS model accuracy. Finally, the lags of the time series data for the Sarab-e Qanbar well including (t-1), (t-2), (t-3) and (t-4) are introduced as the most effective lags.
Reza Karimi; Ali Akbar Akhtari; Omid Seyedashraf
Volume 1, Issue 2 , June 2014, , Pages 61-65
Abstract
Solving a large sparse set of linear equations is of the problems widely seen in every numerical investigation in the entire range of engineering disciplines. Employing a finite element approach in solving partial derivative equations, the resulting stiffness matrices would contain many zero-valued elements. ...
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Solving a large sparse set of linear equations is of the problems widely seen in every numerical investigation in the entire range of engineering disciplines. Employing a finite element approach in solving partial derivative equations, the resulting stiffness matrices would contain many zero-valued elements. Moreover, storing all these sparse matrices in a computer memory would slower the computation process. The objective of this study is to attain insight into Skyline solver in order to store the non-zero valued entries of large linear systems and enhance the calculations. Initially, the Skyline solver is introduced for symmetric or non-symmetric matrices. Accordingly, an implementation of the proposed solver is conducted using various grid form sets and therefore, several stiffness matrices with different sizes to evaluate the solver’s capability in solving equation systems with a variety of dimensions. Comparing the obtained numerical results it was concluded that Skyline algorithm could solve the equation systems tens of times faster than a regular solver; especially in conducting iterative mathematical computations like Saint-Venant Equations.
Elham Darvishi; Tayebeh Kordestani
Abstract
The objective of distribution and delivery of water canal scheduling in irrigation canal networks is timely and adequate delivery of water with minimum operational stages of the head gate of supply canal in the presence of canal capacity and irrigation rotation period constraints. In this paper, two ...
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The objective of distribution and delivery of water canal scheduling in irrigation canal networks is timely and adequate delivery of water with minimum operational stages of the head gate of supply canal in the presence of canal capacity and irrigation rotation period constraints. In this paper, two objective functions, namely, the number of gate changes and the mean discharge for two networks, were minimized by the Genetic and NSGA-II algorithms. The results showed that minimizing these two objective functions at the same time leads to fewer gate changes compared to the only mean canal discharge objective function in both algorithms. It means the mean discharge objective function cannot minimize the number of operational stages alone. Also the optimization by NSGA-II algorithm did not make a significant difference in the results in comparison with the genetic algorithm for both objective functions. However, in NSGA-II algorithm, it is not necessary to determine the weight of each of the objective functions.
Mohammad Reza Boroomand; Nasim Safar Razavi; Ahmad Eshghi
Abstract
The use of a proper leak detection system in pipelines is of crucial importance in water transmission systems. In these methods, we should consider the time and accuracy of leak detecting procedure for preventing energy loss and reducing environmental impacts. In these days, seawater transmission lines ...
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The use of a proper leak detection system in pipelines is of crucial importance in water transmission systems. In these methods, we should consider the time and accuracy of leak detecting procedure for preventing energy loss and reducing environmental impacts. In these days, seawater transmission lines are used for cooling systems, and for injecting water into the oil wells to improve oil recovery. Due to the more environmental impacts of saltwater, the leak detection system must have appropriate accuracy and speed in leak detection. The purpose of this paper is to choose a leak detection system for a saltwater transmission line. First of all, the specifications of different leak detection systems are provided. Finally, according to the mentioned project conditions, the most suitable method -fiber optic system- is recommended for these conditions. The most important advantages of this system are high accuracy, rapid leak detecting, and the ability of online monitoring of other parameters, such as temperature distribution or detecting intrusion into the buried line areas. These abilities result in improving safety and optimizing operating costs.
Nader Bahramifar; Maryam Tavasolli; Habibollah Younesi
Volume 2, Issue 1 , March 2015, , Pages 108-114
Abstract
Biosorption of two anionic dyes, eosin Y and eosin B, from aqueous solution using Saccharomyces cerevisiae was investigated in a batch mode. The influence process parameters such as contact time, initial dye concentration, sorbent dosage, pH and temperature of aqueous solution were studied. The maximum ...
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Biosorption of two anionic dyes, eosin Y and eosin B, from aqueous solution using Saccharomyces cerevisiae was investigated in a batch mode. The influence process parameters such as contact time, initial dye concentration, sorbent dosage, pH and temperature of aqueous solution were studied. The maximum adsorption capacities were found to be at 200 and 100 mg g-1 for eosin Y and 1 eosin B, respectively. The Langmuir and Temkin model were found to be appropriate for the description of biosorption process of eosin Y and eosin B, respectively. The pseudo-second order kinetic model fitted well in correlation to the experimental results for both dyes. Thermodynamic parameters such as enthalpy change (ΔH°), entropy change (ΔS°) and free energy change (ΔG°) were also investigated. Thermodynamic studies indicated that biosorption of both dyes onto S. cerevisiae was an endothermic process. The negative values of free energy change showed that the biosorption of both dyes was spontaneous at the temperatures under investigation. These results indicate that biomass S. cerevisiae particles with clean surface and high porosity are an interesting alternative for dye removal from the wastewater effluents.
Amir Hosein Azimi; Saeid Shabanlou; Behrouz Yaghoubi
Abstract
In this paper, the hydraulic jump length on a slope rough floor is simulated through the extreme learning machine (ELM). Then, the parameters affecting the hydraulic jump on the slope rough bed are detected. After that, five different ELM model are developed so as to determine the influenced factor. ...
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In this paper, the hydraulic jump length on a slope rough floor is simulated through the extreme learning machine (ELM). Then, the parameters affecting the hydraulic jump on the slope rough bed are detected. After that, five different ELM model are developed so as to determine the influenced factor. Next, the results obtained from different ELM models are analyzed. The comparison of the results with the experimental data proves the acceptable accuracy of the mentioned numerical models. Regarding the results from the numerical method, the superior ELM model estimates the hydraulic jump length in terms of the flow Froude number, the ratio of bed roughness, the ratio of sequent depths and bed slope. The values of the root mean square error (RMSE), mean absolute percent error (MAPE), scatter index (SI) and correlation coefficient (R) for the superior model are respectively obtained 0.657, 3.507, 0.052 and 0.985. Based on the simulation, the flow Froude number at upstream is introduced as the most effective parameter in predicting the jump length on the sloping rough floor.
Marjan Nouri; Amirsalar Montazer Faraj
Abstract
Drinking water is one of the main factors for health maintenance and sustainable development of communities and its quantity and quality are so important. The aim of present study is random sampling of drinking water in 30 regions of Tehran city during 2 months in summer of 2020 to determine physicochemical ...
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Drinking water is one of the main factors for health maintenance and sustainable development of communities and its quantity and quality are so important. The aim of present study is random sampling of drinking water in 30 regions of Tehran city during 2 months in summer of 2020 to determine physicochemical attributes, microbial quantity and heavy metal levels according to national standard guidelines. Tests such as pH, alkalinity, turbidity, electrical conductivity, chloride, nitrite level, total and thermotolerant coliforms, and also heavy metals (arsenic, copper, zinc and lead), were performed in three replications. The pH (6.50 to 7.81), turbidity (0.011 to 2.983 NUT), chloride level (240.42 to 321.34 mg/L) and nitrate value (7.21 to 20.04 mg/L) were in allowable ranges. The phenolphthalein alkalinity was not found and methyl orange alkalinity was detected in the range of 31.54 to 147.22 (mg/L) in samples. The electrical conductivity (1401.7 to 1972.1 μs/cm) and thermotolerant coliforms were found higher than allowable range in some samples. The range of heavy metals was represented by following trend in Tehran: arsenic (0.85 to 15.90 μg/L), cooper (0.04 to 3.38 mg/L), zinc (0.16 to 3.80 mg/L), lead (0.001 to 0.031 mg/L) and some ranges were not within the national standard guidelines. The present study illustrated that quality of drinking water was in line with World Health Organization, while microbial quantity, electrical conductivity and some impurities (Cu and Pb) were higher than standard in some regions, so more arrangements should consider for increasing of drinking water quality in Tehran.
Negar Amiri; Mojtaba Ahmadi; Meghdad Pirsaheb; Yasser Vasseghian; Pegah Amiri
Volume 2, Issue 2 , December 2015, , Pages 156-163
Abstract
In this study, ozone combination with a sequencing batch reactor was tested in laboratory scale for treating a soft drink wastewater characterized by high concentrations of chemical oxygen demand (COD). A bench scale aerobic sequencing batch reactor (SBR) is carried out by two stages. The system was ...
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In this study, ozone combination with a sequencing batch reactor was tested in laboratory scale for treating a soft drink wastewater characterized by high concentrations of chemical oxygen demand (COD). A bench scale aerobic sequencing batch reactor (SBR) is carried out by two stages. The system was operated under three different mixed liquid suspended solids (MLSS) concentrations (3000, 4500, 6000 mg/l). The results show that the integrated ozonation with biological process was able to achieve high removal efficiencies for chemical oxygen demand (COD), with residual concentrations much lower than the current discharge limits. Also, the process was characterized by a very low MLSS concentration. Hence, the ratio between ozone dose and the COD removal was 0.72, indicating that the removed COD was higher than the dosed ozone. Artificial neural networks (ANN) was also employed to model the COD data obtained. A network consisting of two layers of five neurons in the hidden layer was considered. Regression coefficient between experimental data and data predicted by neural networks and root mean square error (R2, RMSE) obtained 0.991, 80.36, respectively. Very low error in the network estimation confirmed validity of the obtained networks for further analysis and optimization.
Hadi Ghaebi; Mehdi Bahadorinejad; Mohammad Hassan Saidi
Volume 3, Issue 1 , June 2016, , Pages 201-208
Vitthal L. Gole; Apurva Alhat
Volume 3, Issue 2 , December 2016, , Pages 247-252
Akbar Safarzadeh; Babak Khaiatrostami
Abstract
Water supply from rivers is accomplished with flow diversion through an intake structure. A lateral intake like bifurcation is the simplest method to withdraw water. However, flow at a channel bifurcation is turbulent, highly three-dimensional (3D) and so has many complex features. This paper reports ...
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Water supply from rivers is accomplished with flow diversion through an intake structure. A lateral intake like bifurcation is the simplest method to withdraw water. However, flow at a channel bifurcation is turbulent, highly three-dimensional (3D) and so has many complex features. This paper reports a 3D numerical investigation of these features in an open channel flow. Simulations have been done on rectangular channel geometry, with smooth bed and sidewalls. The standard k-ɛ, k-ω model of the Wilcox, and RSM turbulence models are compared using the commercial code FLUENT. The simulation results have been compared with available experimental data. It was found that all of the turbulence models tested here accurately predicted velocity profiles in the main channel but in the branch channel, the RSM model with the k-ω model performing better than the k-ɛ model. Predicted flow physics are in close agreement with previously reported experimental results.
Mohammad Hossein Karimi Pashaki; Amir Khosrojerdi; Hossein Sedghi
Abstract
The water used in the production process of an agricultural or industrial product iscalled "virtual water". In Iran with low average annual precipitation also lack ofavailable water resources, concept of the virtual water and its trade is used as astrategy for optimal operation of water resources in ...
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The water used in the production process of an agricultural or industrial product iscalled "virtual water". In Iran with low average annual precipitation also lack ofavailable water resources, concept of the virtual water and its trade is used as astrategy for optimal operation of water resources in many fields such as waterscarcity, drought and so on. This concept, also, could hold some interesting newopportunities for the field of sustainable consumption. Recently, in Iran, net virtualwater import reached to (15-20)*109 m3 per year and is one out of the top ten virtualimporting countries. In this research, after virtual water applicable conceptsexpressing, virtual water content in some of the agricultural products in the worldhave been compared with products existence in Iran. Additionally, we selectedsome strategic agricultural products, which export and import to the country, andused an algorithm called "Genetic Algorithm", to optimize virtual water usage andtrade according to demands, agricultural situation, production cost andenvironmental condition. Results showed which products how could help optimalwater resources operation and effect of virtual water usage in economic growth.
Farinaz Ahmadi; Ali Akbar Zinatizadeh; Azar Asadi
Abstract
In this research, the possibility of polyhydroxyalkanoates (PHAs) production in a mixed microbial culture fed by industrial soft drink wastewater was assessed. To enrich the microbial culture, an uncoupled carbon and nitrogen feeding strategy were used in sequencing batch bioreactor (SBR). To evaluate ...
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In this research, the possibility of polyhydroxyalkanoates (PHAs) production in a mixed microbial culture fed by industrial soft drink wastewater was assessed. To enrich the microbial culture, an uncoupled carbon and nitrogen feeding strategy were used in sequencing batch bioreactor (SBR). To evaluate the efficiency of the strategy, PHA, substrate, dissolved oxygen, biomass and nitrogen concentration profiles were reported in the 16th cycles of the SBR. From the obtained data, COD and nitrogen removal efficiencies were 89 % and 75.5 %, respectively at the cycle time of 12h. Also, the maximum poly-hydroxybutyric acid (PHB) content and specific PHA production rate (qp) were achieved as 13.8% (mg-PHB/mg-TSS) and 6.4×10-3 (mg COD-PHA/mg COD-X.h), respectively.